Modelling and analysis of a novel mechanical-variable-flux IPM machine with rotatable magnetic poles

In this study, a novel mechanical-variable-flux interior permanent magnet motor (MVF-IPMM) is presented, which employs rotatable magnetic poles and a mechanical flux-adjusting device placed on both sides of the rotor. The device can regulate the magnetic circuit by rotating magnetic poles and adjusting the angle of the magnetisation direction relative to the d-axis. Consequently, the flux-weakening capability is enhanced. The configuration and additional mechanical devices of the MVF-IPMM are introduced, respectively. Then, the operation principle and flux-adjusting mechanism are deeply investigated by using analytical models, whose parameters are computed by automatic dynamic analysis of mechanical system and finite-element analysis. Based on the simulation results, an electromechanical model is established to predict the performance of the motor. In addition, the electromagnetic characteristics of the mechanical-variable-flux- and conventional interior permanent magnet machines are compared. Finally, the effectiveness of the design is successfully proven by experimenting with a prototype.